There has been known a method for preparing a single-layered microcapsule of polymer comprising the steps of forming a polymer outer layer by performing a polymerization reaction on the surface of a particle having a certain size and degrading or eluting a core material contained therein. In this method, the core material used as a template for forming a capsule can be degraded or eluted only under specific conditions of temperature, pH and a solvent, and thus it is difficult to selectively regulate a material for filling the inside of the particle after the removal of the inner template.
There has been also known another method for preparing a polymer microcapsule where a polymer capsule is formed as a polymer is formed along the interface between droplet surface and a medium by interfacial polymerization using the droplets dispersed in the medium as a core material. Since the selection of a material to fill the inside of the capsule during the capsule polymerization reaction, this method can prepare a polymer capsule containing a certain compound. However, this method has a problem that the core material eluted from the capsule may deform the spherical shape of the capsule, and that the deformed capsules are not able to be introduced with a new compound, thus making it impossible to selectively substitute a core material. Further, in case of forming a thick outer shell to prevent the structural modification of a polymer capsule, it is also not easy to achieve a sufficient elution of a core material.
Meanwhile, for preparing a polymer multi-layered capsule or a polymer-inorganic hybrid multi-layered capsule, there is a method of forming a polymer particle or a polymer capsule and laminating an inorganic precursor or an inorganic particle on the surface thereof, to thereby form a new outer layer on the capsule. Similarly, it is possible to prepare an organic-inorganic multi-layered particle by forming a polymer layer on the surface of an inorganic particle. However, this method has a problem that the polymer outer layer and the inorganic inner layer containing a certain compound inside or having a cavity can be prepared by goring through with a very complicated process. That is, they can be prepared by a multi-step process comprising : (a) forming an inorganic layer on the surface of particles of a template, which enables degradation and elution, (b) removing the inner core material, and (c) forming a polymer layer on the surface thereof. However, in such a case, there has not been known any method for selectively containing or substituting an inner core material.